1. Field of the Invention
The present invention relates to a display system, and more particularly, to a display device checking whether input R,G,B data is normal and a method of detecting an abnormal image signal.
2. Description of the Related Art
Generally, computer systems include a host and a display device. The display device receives Red, Green, Blue (RGB) signals, a horizontal synchronization signal H sync, and a vertical synchronization signal V sync from the host, and displays the received signals on a screen.
Whenever the display device receives an abnormal horizontal synchronization signal or an abnormal vertical synchronization signal from the host, the display device operates according to a suspend mode, a standby mode, or an off mode and informs a user of the generation of this abnormal signal. In the suspend mode, a horizontal synchronization signal is detected but a vertical synchronization signal is not detected. In the standby mode, the vertical synchronization signal is detected but the horizontal synchronization signal is not detected. In the off mode, both the vertical and horizontal synchronization signals are not detected. The display device also informs the user of the input of a vertical/horizontal synchronization signal that does not fall within a signal range prescribed in specifications.
However, even if both the vertical and horizontal synchronization signals are input normally, any, or all of the RGB signals may be abnormally input due to the malfunction of the host. In this case, it is difficult for a user to determine whether the abnormal input of a signal is caused by the malfunction of the display device or the malfunction of the host. Therefore, the user must reboot the host or turn the display device off and on to solve this problem. That is, with a conventional display device, it is difficult to check whether a system is operating normally or abnormally if an R, G or B signal is abnormally input to the display device.